In recent years, transistors having an SiGe layer or an SiGeC layer have received widespread attentions because such a transistor offers potential as an MIS transistor or a bipolar transistor which can operate at high speed. When manufacturing a semiconductor device having such a semiconductor layer, the film thickness and the constituent element content (for example, Ge content in the case of an SiGe layer, and Ge and C content in the case of an SiGeC layer) of the semiconductor layer must be controlled with high precision. Thus, these values must be calculated accurately during inspection.
The spectroscopic ellipsometry method has been proposed for measuring the composition and film thickness of a thin layer formed in semiconductor processes as disclosed, for example, in United States Unexamined Patent Publication No. 2002/0106819 (published on Aug. 8, 2002, Nozawa et al., which is identical to Japanese Unexamined Patent Publication No. 2002-76083).
Known measurement methods adopting spectroscopic ellipsometry, however, still have room for improvement in measurement accuracy. This is because measurement error tends to increase when measuring the constituent element content of an SiGeC layer, particularly.
The X-ray diffraction method (XRD method), secondary ion mass spectrometry method (SIMS method), etc., are known as other methods for measuring the composition and film thickness of a semiconductor layer. These methods can measure the constituent element content with high accuracy. However, large-scale devices, such as an X-ray diffraction device and a mass spectroscope, are required, making these methods inconvenient for measuring at manufacturing sites, and thus are not practical.